Display techniques for three-dimensional virtual reality

ABSTRACT

A limitation of using two-dimensional images, such as videos or photographs, to represent portions of a three-dimensional world occurs when the user moves within the world and views the world from a location different than from the original context of the two-dimensional image, i.e., from a location different than the image&#39;s ideal viewing point (IVP). View changes result in the image not aligning well with the surrounding objects of the three-dimensional world. This limitation is overcome by distorting the two-dimensional image so as to adjust the image&#39;s vanishing point(s) in accordance with the movement of the user using a pyramidic panel structure. In this manner, as the user moves away from the ideal viewing point, the distortions act to limit the discontinuities between the two-dimensional image and its surroundings. To minimize the depth profile of the pyramidic panel structure, the structure may be segmented into sections and each section translated towards, or away from, the user&#39;s viewpoint.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of U.S. patent applicationSer. No. 09/107,059 filed on Jun. 30, 1998 (Case Edmark-2). Theabove-identified co-pending application, which is commonly assigned, isincorporated herein by reference.

TECHNICAL FIELD

This invention relates to the integration of three-dimensional computergraphics and a two-dimensional image to provide a realisticthree-dimensional virtual reality experience.

BACKGROUND OF THE INVENTION

The display of a three-dimensional virtual reality world to a userrequires considerable computation power, and it is typically costly todevelop the necessary highly detailed models required for doing so. Inorder to simplify the problem, two-dimensional images, such as videos orphotographs, may be used to represent or simulate portions of thethree-dimensional world. A great reduction in computation power and costcan be achieved by such an arrangement.

SUMMARY OF THE INVENTION

A limitation of such a world occurs when a user moves within the worldand views the world from a location different than the original contextof a two-dimensional image which has been carefully calibrated to “fitinto” the world. View changes, such as from a location different thanthe image's ideal viewing point, result in the image not aligning orfitting well with the surrounding objects of the three-dimensionalworld. We have recognized that, in accordance with the principles of theinvention, viewpoint changes may be dealt with by distorting thetwo-dimensional image so as to adjust the image's vanishing point(s) inaccordance with the movement of the user using a novel “pyramidic panelstructure.” In this manner, as the user moves away from the idealviewing point, the distortions act to limit the discontinuities betweenthe two-dimensional image and the surroundings of the world. In certainembodiments, the pyramidic panel structure may be segmented intosections, each translated towards or away from the user's viewpoint andthen scaled, so as to minimize the depth profile of the pyramidic panelstructure.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 shows an example of that which a user sees when a user views theworld from the ideal viewing point for a two-dimensional imagerepresenting a portion of the world;

FIG. 2 shows an example of that which a user sees when a user moveswithin the world of FIG. 1 and views the two-dimensional image from alocation different than the image's ideal viewing point, without the useof the present invention;

FIG. 3 shows an exemplary process, in accordance with the principles ofthe invention, for distorting the two-dimensional image using apyramidic panel structure so as to adjust the image's vanishing point inaccordance with the movement of the user;

FIGS. 4 and 5 depict the pyramidic panel structure of the presentinvention for distorting the two-dimensional image so as to adjust theimage's vanishing point, in accordance with the movement of the user;

FIGS. 6A-B depict examples of that which a user sees when a user viewsthe world from a location left of the image's ideal viewing point,without and with the use of the present invention, respectively;

FIGS. 7A-B depict examples of that which a user sees when a user viewsthe world from a location above the image's ideal viewing point, withoutand with the use of the present invention, respectively;

FIGS. 8A-B depict examples of that which a user sees when a user viewsthe world from a location toward the front and the right of the image'sideal viewing point, without and with the use of the present invention,respectively;

FIG. 9 shows an exemplary process, in accordance with the principles ofthe invention, for distorting a two-dimensional image using anarticulated pyramidic panel structure so as to adjust multiple vanishingpoints in the image, in accordance with the movement of the user;

FIG. 10 depicts an example of the articulated pyramidic panel structureof the present invention;

FIG. 11 depicts an example of that which a user sees when a user viewsthe world from a location away from the ideal viewing point of thetwo-dimensional image, with the use of the articulated pyramidic panelstructure of the present invention;

FIGS. 12 and 13 depict side and front views, respectively, of thepyramidic panel structure of FIG. 5 with each panel segmented into aplurality of sections;

FIG. 14 depicts the pyramidic panel structure of FIG. 5, with each panelsegmented into a plurality of sections having its centers located on thesurface of a predetermined plane; and

FIG. 15 depicts the pyramidic panel structure of FIG. 5, with each panelsegmented into a plurality of sections and each section translated adifferent distance toward the user's view point, V.

DETAILED DESCRIPTION

To better understand the invention, FIGS. 1-2 show examples of thatwhich a user sees when the user moves within a three-dimensional virtualreality world (x,y,z) and views a two-dimensional image (x,y)representing a portion of the world from a location at the image's idealviewing point (IVP), and then from a different location, i.e., alocation different than the original context of the image. It should beunderstood that the two-dimensional image has been carefully calibratedto “fit into” the surroundings of the world. For simplification ofterminology purposes, we shall use the term two-dimensional image todenote either a video clip or a photograph. In accordance with theprinciples of the invention, as the user moves away from the idealviewing point, discontinuities between the two-dimensional image and itssurroundings are minimized by distorting the image according to themovement of the user.

FIG. 1 shows an exemplary three-dimensional reality world 105, which isa bicycle path in a park, e.g., Central Park in New York City. Inrepresenting world 105, the present invention exploits a characteristiccommon for images consisting of views looking down the center of roads,streets or paths, which is that they may be treated as perspective,corridor-like images, with features closer to the center of the imagebeing farther away from the viewer along the z-axis. Accordingly, thebicycle path or road and its immediate vicinity are treated as a kind ofthree-dimensional, corridor-like image whose floor is formed by theroadbed, whose ceiling is formed by the sky, and whose sidewalls areformed by the roadside objects. In this manner, the principles of asimple point perspective can be used for distorting the landscape imagein accordance with the movement of the viewer, as discussed hereinbelow.

World 105 is divided into two portions, screen or panel 110 on which isshown or displayed a two-dimensional image 115, such as a stillphotograph, picture, or a current frame of a video clip; and theremainder of the world 120, which is represented using computer graphicstechniques, and is thus referred to herein as computer graphics (CGPart) 120. Within CG Part 120 there are various synthetic,three-dimensional landscapes or objects modeled in, for example, theVirtual Reality Modeling Language (VRML). Two-dimensional image 115simulates landscape or terrain portions of the world 105, here a virtualroad or course 125 for walking, running or pedaling a bicycle.

Note that although three-dimensional world 105 cannot be actuallyrendered in a two-dimensional plane (x,y), it can be projected to anddisplayed on a two-dimensional plane so as to appear to have threedimensions (x,y,z). Accordingly, the techniques of the present inventionare preferably employed with computers and software, which aresufficiently sophisticated to display images on a two-dimensional planeas having three dimensions. Note also that to make the world lookrealistic, computer graphics display techniques use the z component ofobjects to scale accordingly the x and y components as a function of itsdistance (z-axis) to the user's viewpoint.

Two-dimensional image 115 is carefully placed, cropped and sized toachieve continuity with the surrounding environment of the CG Part 120.Note that the image is clipped so that the left and right edges of theroad in CG Part 120 pass through the left and right bottom comers of theroad, respectively, in image 115. This clipping ensures that the roadbedmaps to the floor of the hypothetical corridor. In so doing, portions atthe boundary between two-dimensional image 115 and CG part 120 areco-planar, i.e., at the same distance away along the z-axis from theuser's viewpoint. In “fitting” two-dimensional image 115 to CG part 120,however, there exits only one viewpoint from which that image's contentproperly corresponds to the surrounding environment of CG Part 120. Thisunique location is called the image's ideal viewing point (IVP). In FIG.1, two-dimensional image 115 is seen from its ideal viewing point, andfrom this view, image 115 aligns well with the surrounding objects of CGPart 120.

Users, however, rarely view image 115 only from its idea viewing point.As the user moves within world 105, such as left or right of road 125,as they round curves, or move closer to or farther from the image, theysee image 115 from positions other than its ideal viewing point. Absentthe use of the present invention, such viewpoint changes would causeobjects or features within image 115 to align improperly with thesurrounding environment, as further illustrated in FIG. 2.

In accordance with the principles of the invention, however, screen orpanel 110 uses a display structure called a “pyramidic panel structure”for displaying two-dimensional image 115 within the surroundingthree-dimensional space of the CG Part 105 so as to deal with viewpointchanges. The transformations associated with the pyramidic panelstructure dynamically distort two-dimensional image 115 according toviewer's position so as to adjust the image's vanishing point with theviewer's movement. As the viewer moves from the image's ideal viewingpoint, these distortions act to limit discontinuities between image 115and the surroundings of CG Part 120.

FIG. 3 shows an exemplary process in accordance with the principles ofthe invention for distorting two-dimensional image 115 so as to adjustits vanishing point in accordance with the viewer's position. Theprocess is entered at step 130 whenever it is determined that theviewer's position has changed.

Using the virtual world's road model of the CG Part 105, a vector,{overscore (C)}, corresponding to the direction of road 125 is projectedat step 135 from the image's ideal viewing point, IVP, to panel orscreen 110 on which is displayed image 115. Note that the panel istwo-dimensional, but represents three-dimensional space with objectsnearer the center of the image being farther away from the plane of theviewer. The panel structure is shown in FIG. 4. The point ofintersection with screen or panel 110 is the image's vanishing point, P.Note, however, that the vanishing point may be set visually by the user,if desired, or by other suitable computer graphics processing techniquesknown in the art. Next, in step 140, screen or panel 110 is segmentedinto four triangular regions 145 ₁₋₄, one for each of the regionsbordering CG Part 120, with the intersection point of the four regionslocated at the vanishing point, P.

Thereafter in step 150, the current viewpoint of the user, V, isdetermined, and a vector {overscore (T)} projected from the idealviewing point, IVP, to the viewer's current location, V. In accordancewith the principles of the invention, as the viewer moves, a newvanishing point P′ is calculated as P′=P+{overscore (T)}. The fourtriangular regions 145 ₁₋₄ are distorted in the three-dimensional spaceof the virtual world at step 155 to represent the mapping of objectsnearer the center of the image being displaced farther away from theviewpoint of the user. The four triangular regions intersect at the newvanishing point P′ and form so-called “pyramidic panels” 145′₁₋₄. Thisis illustrated in FIG. 5. At step 160, the corresponding imagesdisplayed in regions 145 ₁₋₄ are then “texture-mapped” onto pyramidicpanels 145′₁₋₄, respectively. In this manner, as the viewer moves awayfrom the image's ideal viewing point, IVP, distortions in the imageresulting from moving the image's vanishing point from P to P′ act tolimit the discontinuities between image 115 and the surroundings withinCG Part 105.

In the exemplary illustration of FIG. 5, distorting image 115 so as tomove the vanishing point from P to P′ results in pyramidic panelstructure forming a four-sided pyramid. Note that its base is fixed andcorresponds to original screen or panel 110, with its peak located atP′, which moves in concert with the viewer's current location, V. As theuser's viewpoint moves closer to and farther from the image, the image'svanishing point accordingly moves farther from and closer to the user'sviewpoint, respectively.

FIGS. 6 through 8 compare the display of two-dimensional image 115 onscreen or panel 110 with the display of the same image using the“pyramidic” panels of the present invention. More specifically, FIGS.6A, 7A and 8A depict viewing two-dimensional image 115 at a locationfrom the left, above, and in front and to the right of the image's idealviewing point, IVP, respectively, without the use of the presentinvention. In these latter figures, note that there are discontinuitiesbetween the edges of the road and the three-dimensional space of CG Part105. FIGS. 6B, 7B and 8C depict the same two-dimensional image distortedand texture-mapped onto pyramidic panels 145′₁₋₄, in accordance with theprinciples of the invention. Note that in these latter figures, thediscontinuities in the road edge have been substantially eliminated.

In another embodiment of the present invention, a modified pyramidicpanel structure may be used to deal with two-dimensional imagescontaining curved roads, streets, paths and other corridor-like imagescontaining multiple rather than a single vanishing point. In this lattercase, screen or panel 110 is segmented using multiple vanishing pointsto form a so called “articulated pyramidic panel structure.” Thetransformations associated with the articulated pyramidic panelstructure dynamically distort different portions of two-dimensionalimage 115 according to viewer positions so as to adjust the differentvanishing points of the image with the viewer's movement. Likewise, asthe viewer moves from the image's ideal viewing point, these distortionsact to limit the discontinuities between two-dimensional image 115 andthe surroundings of CG Part 120.

FIG. 9 shows an exemplary process in accordance with the principles ofthe invention for distorting two-dimensional image 115 using anarticulated pyramidic panel structure. Again, the process is entered atstep 170 whenever it is determined that the viewer's position haschanged. In general, curve road 125 is treated as two straight corridorsplaced end-to-end, extending back from screen or panel 110. Eachcorridor represents a different portion of road 125 in thethree-dimensional space of world 105, with features nearer the center ofthe image being farther away from the user's viewpoint.

Using the virtual world's road model of the CG Part 105, correspondingdirectional vectors C₁ and C₂ of the corridors are determined at step175. Note that portion of the road nearer to the user's viewpoint isrepresented by C₁, and the portion farther away is represented by C₂.Next, in step 180, using the vectors C₁ and C₂, the correspondingvanishing points P₁ and P₂ are determined, respectively, for eachcorridor by projecting those vectors from the image's ideal viewingpoint, IVP. Alternatively, vanishing points P₁ and P₂ may be determinedvisually by the user, or by some other suitable means known in the art.In step 185, using the first corridor's vanishing point, P₁, a first setof pyramidic panels 190 ₁₋₄ are constructed to intersect at vanishingpoint, P₁, as shown in FIG. 10.

Now at step 195, a coupling ratio α is calculated according to thefollowing equation: α=l/(l+d), where 1 is the length of the firstcorridor, and d is the distance between the image's ideal view point(IVP) and the base of pyramidic panels 190 ₁₋₄. Each line segmentconnecting a corner of the base to vanishing point P₁ is then dividedinto two segments by a point placed according to the coupling ratio, α.More specifically, the length l′ of each line segment from the corner ofthe base of panels 190 ₁₋₄ to this point is given by l′=αl″, where l′ isthe total length of the segment between the corner of the panel and thevanishing point, P₁. These four points labeled Q1 through Q4 areconnected to form the base of a second set of smaller pyramidic panels200 ₁₋₄ embedded within the larger panels (step 205), as furtherillustrated in FIG. 10. The intersection point of pyramidic panels 200₁₋₄ is then moved from P₁ to vanishing point, P₂.

For the articulated pyramidic panel structure, the current viewpoint ofthe user, V, is determined, and a vector {overscore (T)} projected fromthe ideal viewing point, IVP, to the viewer's current location, V (step210). As the viewer moves, a new vanishing point P′₂ is calculated asP₂′=P₂+{overscore (T)} at step 215, and panels 200 ₁₋₄ are thendistorted so as to intersect at P′₂. As the viewer move, the fourinternal points Q1 through Q4 are mapped with the viewer's movement toQ1′ through Q4′, respectively, in accordance with the followingrelationship: Q_(i)′=Q_(i)+α{overscore (T)}, at step 220. Note thatdoing so, accordingly distorts the first set of pyramidic panels 190₁₋₄. At step 225, the corresponding images in original panels are thentexture-mapped into articulated pyramidic panels 190 ₁₋₄ and 200 ₁₋₄,which have been distorted in accordance with the movement of the viewer.Note that to unambiguously texture-map onto panels 190 ₁₋₄, these panelsare each subdivided into two triangular subregions and thentexture-mapped. Shown in FIG. 11 is image 115 seen from a location awayfrom the image's ideal viewing point, using the articulated pyramidicpanel structure of the present invention.

Note that the above articulated pyramidic panel structure may also usemore than two sets of pyramidic panel structures. Instead of treatingthe curve road as two straight corridors, multiple corridors may beemployed, each placed end-to-end and extending back from screen or panel110. Likewise, each corridor represents a different portion of road 125in the three-dimensional space of world 105, with features nearer thecenter of the image being farther away from the user's viewpoint. Insuch a case, each set of articulated pyramidic panels are formedreiteratively using the above described procedure.

Referring to FIGS. 12-13, there is shown a third embodiment of thepresent invention which is similar to that of FIG. 5 and in which“pyramidic panels” 145′₁, 145′₂, 145′₃ and 145′₄ have been nowmulti-segmented into sections 205 ₁₋₄, 210 ₁₋₄, 205′₁₋₄, and 210′₁₋₄,respectively, with the images in original panels 145 ₁₋₄ thentexture-mapped into the corresponding translated sections of thepyramidic panel structure, as discussed herein below. It should berecalled that the pyramidic panel structure represents thethree-dimensional mapping (x,y,z) of two-dimensional image 115 ontoimage screen or panel 110 (x,y). Advantageously, the embodiment of FIGS.12-13 minimizes the depth profile of the pyramidic panel structure alongthe z-axis. Unlike the embodiment of FIG. 5, the depth profile of thisthird embodiment does not substantially vary with changes in the user'sviewpoint, V. In the exemplary embodiment of FIG. 5, recall thatdistorting image 115 so as to move the vanishing point from P to P′results in the pyramidic panel structure forming a four-sided pyramid.The base of the pyramid is fixed and corresponds to original screen orpanel 110, with its peak located at P′ and moves in concert with theviewer's current location, V. As the user's viewpoint moves along thez-axis closer to and farther from two-dimensional image 115, the image'snew vanishing point P′ moves farther from and closer to the user'sviewpoint, respectively. This latter movement causes the depth profilealong the z-axis of the pyramidic panel structure to vary accordingly.Unfortunately, this variation in depth profile can undesirably and/orunexpectedly occlude from the user's view objects in the virtual world,or cause objects to occlude other features in the virtual world inasmuchas the corresponding images in the panels are distorted, as discussedabove herein.

To obviate the aforementioned problem, “pyramidic panels” 145′₁, 145′₂,145′₃ and 145′₄ have been multi-segmented into sections 205 ₁₋₄, 210₁₋₄, 205′₁₋₄, and 210′₁₋₄ respectively. Each section is then translatedalong the z-axis to a predetermined distance towards or away from theuser's viewpoint, V, but importantly of the same orientation as theoriginal section. For example, segmented sections 205 ₁₋₄ and 205′₁₋₄may each have one of its outer edge along the x-axis translated to lieon the x,y plane of screen or panel 110, as shown in phantom in FIG. 12.As the user moves to a new viewpoint, each section in effect pivotsabout that edge along the x-axis, which edge lies on the surface ofpanel 110. Similarly, section 210 ₁₋₄ and 210′₁₋₄ may each have one ofit outer edge along the y-axis lying on the surface of panel 110.Alternatively, sections 205 ₁₋₄, and 205′₁₋₄ may be centered along panel100, as depicted in FIG. 14. Likewise, sections 210 ₁₋₄ and 210′₁₋₄ maybe similarly translated, but for the sake of clarity are not shown inFIGS. 12 and 14.

Still further, each of sections 205 ₁₋₄ and 205′₁₋₄ may in effect berotated or pivoted about its other edge along the x-axis as the usermoves to a new viewpoint, V, or, in general, about an axis parallel withan edge along the x-axis of the corresponding section. Again, thislatter axis may, but does not have to, lie on the surface of panel 110.Regardless of the segmenting method chosen, however, translating eachsection towards or away from the user's viewpoint significantly reducesthe depth profile of the pyramidic panel structure along the z-axis,such as depicted in FIG. 12 from, for example, T₂ to T₁.

In still another embodiment of the present invention, sections 205 ₁₋₄and 205′₁₋₄ may each be translated a different distance along thez-axis, as illustrated in FIG. 15. Although not shown, sections 210 ₁₋₄and 210′₁₋₄ may likewise be translated. Those skilled in the art willreadily understand that doing so advantageously allows the user'sviewpoint, V, to extend in front of panel 110 inasmuch as segmentedsections corresponding to the image's center may be offset and locatedcloser to the user's viewpoint, V, than the outer sections.

Also, note that segmenting the pyramidic panel structure into a greaternumber of smaller sections accordingly only further reduces the depthprofile, which asymptotically approaches a zero thickness. It iscontemplated that the number of sections that the panel structure isdivided into may be chosen empirically based on image content as well asthe user's range of movement within the virtual world. Preferably,however, the panel structure is dynamically segmented in a reiterativemanner. For example, once a user has chosen the maximum desired depthfor the panel structure along the z-axis to minimize occlusion, eachpanel is then reiteratively segmented into a greater number of smallersections until the depth profile is reduced to the maximum depth profiledesired.

In accordance with the principles of the invention, it should be clearlyunderstood, however, that to maintain the apparent integrity oftwo-dimensional image 115 when texture-mapping the image onto thesegmented sections, each segmented sections 205 ₁₋₄, 205′₁₋₄, 210 ₁₋₄,and 210′₁₋₄ is scaled accordingly with respect to the user's currentviewpoint, V, so as to appear to be of the same size as the originalcorresponding section. This scaling or transform is given by:$S_{t} = {S_{p}\frac{T_{t}}{T_{p}}}$

where S_(p) is the size of the original pyramidic section; S_(t) is thesize of the translated, segmented pyramidic panel section; T_(p) isdistance to the original pyramidic section from the user's viewpoint, V;and T_(t) is the distance to the translated, segmented pyramidicsection. In other words, each segmented, translated section is scaled bythe ratio T_(t)/T_(p). Of course, as the user moves within the world,pyramidic panels 145′₁₋₄ are accordingly re-segmented, translated, andthen scaled with respect to the user's new viewpoint, V. Then, theimages in original panels 145 ₁₋₄ are again accordingly texture-mappedinto the corresponding translated sections 205 ₁₋₄, 205′₁₋₄, 210 ₁₋₄,and 210′₁₋₄ of the pyramidic panel structure.

The foregoing merely illustrates the principles of the invention. Itwill thus be appreciated that those skilled in the art will be able todevise various arrangement which, although not explicitly describe orshown herein, embody the principles of the invention and are includedwithin its spirit and scope.

What is claimed is:
 1. A method for use in processing a view of athree-dimensional world in which a first portion of said world ismodeled as computer graphics and a second portion of said world isrepresented by a two-dimensional image texture-mapped on a panel,comprising the steps of: determining the current viewpoint of the user,V; dividing the panel into triangular regions; distorting the triangularregions to form pyramidic panels such that a corresponding vanishingpoint, P, of a portion of the two-dimensional image moves as a functionof the current viewpoint of the user; segmenting each of said pyramidicpanels into a plurality of sections; translating each of said pluralityof sections of said pyramidic panels towards, or away from, said currentviewpoint of the user, V; texture-mapping the two-dimensional image ontothe plurality of sections of the pyramidic panels; and as the user moveswithin the three-dimensional world, repeating the above steps so as tolimit discontinuities between the two-dimensional image and the computergraphics.
 2. The invention as defined in claim 1 wherein said segmentingstep includes resegmenting said pyramidic panels into a greater numberof smaller sections until the depth profile of the pyramidic panelstructure formed from said panels reaches a predetermined level.
 3. Theinvention as defined in claim 1 wherein an outer edge of each of saidplurality of sections of said pyramidic panels is located on the surfaceof a predetermined plane.
 4. The invention as defined in claim 3 whereinsaid predetermined plane is the panel onto which the two-dimensionalimage texture-mapped.
 5. The invention as defined in claim 1 wherein thecenter of each of said plurality of sections of said pyramidic panels issubstantially located at the surface of a predetermined plane.
 6. Theinvention as defined in claims 5 wherein said predetermined plane is thepanel onto which the two-dimensional image is texture-mapped.
 7. Theinvention as defined in claim 1 further comprising scaling each of saidplurality of sections of said pyramidic panels in accordance with thefollowing relationship ${S_{t} = {S_{p}\frac{T_{t}}{T_{p}}}},$

where S_(p) is the size of the section; S_(t) is the size of thetranslated section; T_(p) is distance the section from the user'sviewpoint, V; and T_(t) is the distance to the translated section fromthe user's viewpoint, V.
 8. The invention as defined in claim 1 furthercomprising determining a vector, {overscore (C)}, corresponding to thedirection of a portion of a path contained within the two-dimensionalperspective image, and projecting toward the panel the vector,{overscore (C)}, from the image's ideal viewing point, IVP, theintersection of said vector, {overscore (C)}, with the panel beingdenoted as the image's vanishing point, P.
 9. The invention as definedin claim 1 wherein said distorting of the triangular regions in saiddistorting step includes determining a new vanishing point, P′, for saidtwo-dimensional image in accordance with the following relationshipP′=P+{overscore (T)}, wherein {overscore (T )}is a vector from theimage's ideal viewing point, IVP, to the current viewpoint, V.
 10. Theinvention as defined in claim 1 further comprising the step ofcalibrating the two-dimensional perspective image as a function of thedimensions of the surroundings within the world.
 11. The invention asdefined in claim 1 wherein said two-dimensional perspective image is aframe of a video.
 12. The invention as defined in claim 1 wherein saidtwo-dimensional perspective image is a still picture.
 13. A method foruse in processing a view of a three-dimensional world in which a firstportion of said world is modeled as computer graphics and a secondportion of said world is represented by a two-dimensional imagetexture-mapped on a panel, said two-dimensional image including anobject depicted in perspective, said image being such that features ofthe object closer to a predetermined point of the image are farther awayfrom a user's viewpoint, comprising the steps of: determining a vector,{overscore (C)}, corresponding to the direction of said perspectiveobject in the three-dimensional world; projecting towards said panel thevector, {overscore (C)}, from the two-dimensional image's ideal viewingpoint, IVP, the intersection of said vector, {overscore (C)}, with thepanel being denoted as the image's vanishing point, P; segmenting saidpanel into triangular regions intersecting at the image's vanishingpoint, P; determining the current viewpoint, V, of the user andprojecting a vector, {overscore (T)}, from the image's ideal viewingpoint, IVP, to the current viewpoint, V; determining a new vanishingpoint for the two-dimensional image in accordance with the followingrelationship P′=P+{overscore (T)}; distorting the triangular regions inthe space of the three-dimensional world such that they intersect at thenew vanishing point, P′; segmenting each of said triangular regions intoa plurality of sections; translating each of said plurality of sectionsof said triangular regions towards, or away from, said current viewpointof the user, V; and texture-mapping the two-dimensional image in thetriangular regions onto the corresponding sections of said triangularregions.
 14. The invention as defined in claim 13 wherein saidsegmenting step of said triangular regions includes resegmenting saidtriangular regions into a greater number of smaller sections until thedepth profile of the pyramidic panel structure formed from saidtriangular regions reaches a predetermined level.
 15. The invention asdefined in claim 13 wherein said predetermined point is substantiallynear the center of the two-dimensional image.
 16. The invention asdefined in claim 13 further comprising displaying the texture-mappedtwo-dimensional image merged with the first portion of said world thatis modeled as computer graphics.
 17. The invention as defined in claim13 further comprising the step of calibrating the two-dimensional imageas a function of the dimensions of the surroundings within the world.18. The invention as defined in claim 13 wherein an outer edge of eachof said plurality of sections of said triangular regions is located onthe surface of a predetermined plane.
 19. The invention as defined inclaims 18 wherein said predetermined plane is the panel onto which thetwo-dimensional image is texture-mapped.
 20. The invention as defined inclaim 13 wherein the center of each of said plurality of sections ofsaid triangular regions is located on the surface of a predeterminedplane.
 21. The invention as defined in claim 20 wherein saidpredetermined plane is the panel onto which the two-dimensional image istexture-mapped.
 22. The invention as defined in claim 13 furthercomprising scaling each of said plurality of sections of said triangularregions in accordance with the following relationship${S_{t} = {S_{p}\frac{T_{t}}{T_{p}}}},$

where S_(p) is the size of the section; S_(t) is the size of thetranslated section; T_(p) is distance to the section from the user'sviewpoint, V; and T_(t) is the distance to the translated section fromthe user's viewpoint, V.
 23. An apparatus for use in processing a viewof a three-dimensional world in which a first portion of said world ismodeled as computer graphics and a second portion of said world isrepresented by a two-dimensional perspective image, said apparatuscomprising: means for determining the current viewpoint of the user, V;means for dividing the panel into triangular regions; as the user moveswithin the three-dimensional world, means for dynamically distorting thetriangular regions to form pyramidic panels such that a correspondingvanishing point, P, of a portion of the two-dimensional image moves as afunction of the current viewpoint of the user; means for segmenting eachof said pyramidic panels into a plurality of sections; means fortranslating each of said plurality of sections of said pyramidic panelstowards, or away from, said current viewpoint of the user, V; and meansfor texture-mapping the two-dimensional image onto the plurality ofsections of the pyramidic panels.
 24. The invention as defined in claim23 wherein an outer edge of each of said plurality of sections of saidpyramidic panels is located on the surface of a predetermined plane. 25.The invention as defined in claim 24 wherein said predetermined plane isthe panel onto which the two-dimensional image is texture-mapped. 26.The invention as defined in claim 23 wherein the center of each of saidplurality of sections of said pyramidic panels is located on the surfaceof a predetermined plane.
 27. The invention as defined in claim 23further comprising means for scaling each of said plurality of sectionsof said pyramidic panels in accordance with the following relationship${S_{t} = {S_{p}\frac{T_{t}}{T_{p}}}},$

where S_(p) is the size of the section; S_(t) is the size of thetranslated section; T_(p) is distance to the original section from theuser's viewpoint, V; and T_(t) is the distance to the translated sectionfrom the user's viewpoint, V.
 28. The invention as defined in claim 23further comprising means for determining a vector, {overscore (C)},corresponding to the direction of a portion of a path contained withinthe two-dimensional perspective image, and means for projecting towardthe panel the vector, {overscore (C)}, from the image's ideal viewingpoint, IVP, the intersection of said vector, {overscore (C)}, with thepanel being denoted as the image's vanishing point, P.
 29. The inventionas defined in claim 23 wherein said means for distorting the triangularregions includes means for determining a new vanishing point, P′, forsaid two-dimensional image in accordance with the following relationshipP′=P+{overscore (T)}, wherein {overscore (T)} is a vector from theimage's ideal viewing point, IVP, to the current viewpoint, V.
 30. Theinvention as defined in claim 23 further comprising means forcalibrating the two-dimensional perspective image as a function of thedimensions of the surroundings within the world.
 31. The invention asdefined in claim 23 wherein said two-dimensional perspective image is aframe of a video.
 32. The invention as defined in claim 23 wherein saidtwo-dimensional perspective image is a still picture.